Andy Murray
Tennis
The tennis ace has been training with Rafael Nadal in Majorca ahead of the Rio Olympics and now it's his time to shine. Following on from his second win at Wimbledon in July, Andy is hoping to secure another victory in Brazil.
The Scotsman, who welcomed his first child baby Sophia with his wife Kim in February, has participated in the Beijing 2008 and London 2012 Games.
His Olympic victory over Roger Federer in 2012 proved to be a watershed moment for Andy, who picked up a gold. He also scooped a silver in the mixed doubles alongside Laura Robson.
Usain Bolt
Athletics
It's always a thrilling experience to watch the fastest man in the world on the Olympic track. This year promises to be no different with Usain Bolt hoping for a "triple-triple" – winning gold in all three of his events, the 100m, 200m and 4x100m events.
The Jamaican sprinter has pledged to defend his titles and arrived in Brazil one week before the Games. "I know the sport needs me to win and come out on top," said Usain.
Jessica Ennis-Hill
Athletics – Heptathlon
Last summer Jessica Ennis-Hill made the mother of all comebacks when she won gold at the World Athletics Championship, just 13 months after giving birth to her son Reggie.
The mum-of-one is no doubt hoping to secure a similar triumph at this summer's Olympics as she competes in the heptathlon events.
While injury denied her the chance to complete at the 2008 Olympics, she had her moment in the spotlight at London 2012. On Super Saturday, Jessica joined Mo Farah and Greg Rutherford on the top step of the podium for Great Britain.
Ryan Lochte
Swimming
Three-time Olympian Ryan Lochte, who is often dubbed Michael Phelps' long-time rival, is one of the stars of Team USA that fans can't wait to see.
Ryan has 11 Olympic medals under his belt – five gold, three silver and three bronze – and he has qualified for the Rio Games, where he will swim in the 200m individual medley and the 4x200m freestyle event.
His drive to win stems from his teenage days when Ryan lost at the Junior Olympics. "I suddenly said, 'I'm sick of losing'. After that I trained hard and I never lost there again," he said.
Mo Farah
Athletics
He made history last summer when he became the first man to win the "triple double" – medals in the 5,000 and 10,000 track running events at an Olympics and two world championships – so it's no surprise that fans can't wait to cheer him on at Rio.
Mo Farah, who is based in Portland, Oregon with his wife and four children, will be competing in the athletics events this summer.
The two-time Olympic champion won gold at the 5,000m and 10,000m races at London 2012. He is also a five-time European champion with gold medals from Barcelona, Helsinki and Zurich as well as a silver medal from Goteborg in 2006.
Michael Phelps
Swimming
He is the most decorated Olympian of all time with 22 medals to his name, so it's no wonder Michael Phelps makes a splash every time he slips into the pool.
This year, the four-time Olympian will compete in the 100m butterfly, 200m butterfly and 200m individual medley events as part of Team USA.
Michael has struck gold in his home life too. The new dad has just welcomed his first baby, a son Boomer, with his fiancée Nicole Johnson. The little boy, who was born in May, has already taken his first dip in the pool with his pro swimmer dad.
Greg Rutherford
Athletics
The athlete won his first national long jump title in 2005 and at the 2012 London Olympics, Greg Rutherford went for gold. Ever since, fans have considered him one of Team GB's all-time greats.
His partner Susie Verrill revealed earlier this year that she and the couple's son Milo won't be flying to Rio, amid fears over the Zika virus.
She wrote in her blog post: "With the father of my son one of the big names and the weight of cementing his title on his shoulders, I’ll be nervously watching not just as a keen spectator but as someone who wants to see their other half achieve their dreams. I can confirm, however, that we will be watching from home."
She added: "The Zika news has caused no end of concern if we’re totally honest. We’re not ones to worry unnecessarily, but after more than 100 medical experts stressed the Games should be moved to prevent the disease from spreading, this was a huge factor in us choosing to stay put.
"We’ve also made the decision to have Greg’s sperm frozen. We’d love to have more children and with research in its infancy, I wouldn’t want to put myself in a situation which could have been prevented."
Tom Daley
Diving
Making his Olympic debut at the Beijing Games in 2008, Tom Daley's most celebrated medal to date came in 2012 when he scored a bronze in the 10m platform event.
The 22-year-old is now gearing up for Rio and in a new documentary entitled Tom Daley: Diving For Gold, Tom opened up about how the death of his father in 2011 changed him as a person.
"It's been weird adapting to life without him but all the lessons that he's taught me, I've tried to live by," said Tom. "I think he's really shaped me into the person that I am today."
His fiancé Dustin Lance Black is confident that Tom can go for gold.
"I know Tom can win the gold," said Dustin. "His coach knows he can win gold. There's no question Tom can win gold in Rio. The question is, does Tom believe it? There are days he does and there are days I'm not sure he does yet."
Nicola Adams
Boxing
Nicola Adams made history when she became the first woman to win an Olympic boxing gold medal in 2012. She lit up the ring a second time in 2014, again taking home gold at the Commonwealth Games in Glasgow.
The star, who was awarded an MBE in 2013, is arguably the most recognised female boxer in Great Britain.
Speaking about her power as a role model, Nicola told The Telegraph: "People didn't know girls did taekwondo or boxing and judo. It has had a massive impact. It shows the power of TV, and the power of the Olympics."
She added of having fun in the ring: "It's just a sport for me; I don't see it as a fight."
Louis Smith
Gymnastics Artistic
All eyes will be on the gymnast following his success at the London 2012 Games, where he picked up a bronze medal at the men's artistic team all-round event.
In 2008, Louis was also the first British male gymnast to win an Olympic medal since Walter Tysall at London 1908 when he won pommel bronze.
Now with Rio on the horizon, Lucy Mecklenburgh's ex-boyfriend is gearing up for the gymnastics artistic events.
He told HELLO! Online earlier this year: "If I won an Olympic gold medal, my first thing I'd want to do is see my mum and my coach. If they're back home, I'd ring or FaceTime them.
"Once I'd done all the pleasantries, thanked all the people I needed to thank, done all the interviews and done all my drug tests, I'd get home, shower, put a shirt and jeans on and then I'd go out and party."